Field of the Invention
The invention relates to a control device, in particular for an automatic motor vehicle transmission, including an electronic circuit, the electronic circuit is mounted on a substrate and accommodated in a housing that is sealed with respect to a surrounding fluid, and the electronic circuit is connected to electrical conductors that run outside the housing.
Such control devices are used in motor vehicles, in particular as control devices for automatic transmissions. Advanced electronic transmission control devices are integrated directly into the transmission for reasons of costs and quality. For that purpose, a housing containing the transmission controller is integrated into the transmission housing. Such a transmission controller, which is also referred to as being fully integrated, is described in Published European Patent Application 0 758 726 A2, corresponding generally to U.S. application Ser. No. 09/042,449, filed Mar. 16, 1998.
In order to be suitable for installation in a transmission housing, the control device must be capable of functioning over a wide temperature range, for example from -40.degree. C. to 140.degree. C. In addition, it must be sealed with respect to all customary types of transmission oil (so-called ATF oils), and finally it must be sufficiently vibration-proof (for example up to accelerations of 20 g).
It is known to seal components which are accommodated on a carrier plate mounted in the interior of the housing of the control device with a silicone rubber in commercial practice. The sealing compound is introduced at room temperature and then cured at an elevated temperature (for example at 110.degree. C. for one hour). The housing of the control device must be very carefully sealed in order to reliably prevent the ingress of transmission oil. The ingress of transmission oil into the control device would cause the silicone rubber to swell up, as a result of which, in particular, bonding wires could be damaged, leading to a failure of the control device.